Great advances have been made in the building industry with respect to forming curbs, gutters, curbs and channels, and the like. Not many years ago, it was necessary to assemble wooden forms by hand, a section at a time, into the desired curb shape. This assembly of forms required a considerable amount of skill and preparation time. Further, once the concrete or cement had been poured into the prepared form and properly cured, the wooden forms, usually reusable, were disassembled and then reassembled for another section of the curbing. This process consumed much time and consequently was very expensive.
Within the last few decades, slip-form curb making machines have been developed which produce curbs, barrier walls and the like. Typically, to be economically feasible, these curb making machines were large bulky machinery utilized almost exclusively for highway or roadway use where vast distances of curbing or barrier walls were being formed. Operation of such machinery may require several workmen and substantially level surfaces upon which the curbing is to be formed.
Slip-form curb making machines are complex machines having many working parts. Such machines usually comprise a hopper for receiving and storing the concrete, cement, or some other building material; an extrusion mold which shapes the material before it is extruded; a feed mechanism for forcing the material into the extrusion mold; and some type of steering mechanism. Some of the curb machines are vehicles in which the operator rides on the vehicle itself while steering it in a manner similar to a tractor or a truck. Other curb making machines are designed to follow a railing or track which is prepared in advance. Some of the curb making machines are propelled by an engine or motor. Others are propelled by a winch which drags the vehicle on a cable. Still others are set on wheels or sled-like runners and are propelled by the pushing action of the feed mechanism compacting fresh material against the extruded curbing.
Several types of feed mechanisms have been used in curb making machines. Auger screws have been used to deliver the concrete, cement, or other building material to the extrusion mold. Piston and plunger assemblies and reciprocating ramming plates have also been used to deliver and compact such materials. Such feed mechanisms serve to vibrate or agitate the building material being used and to compact such material so as to fill the mold and to eliminate undesirable voids and weaknesses in the material.
Only recently have small hand operated, power driven curb making machines been developed which can be feasibly and economically used for yard use or for small applications where the large highway curb machines are impractical. The forerunner of such machines were small wheel-barrow like devices which required manpower to propel the device along the ground and to operate the plunger or ramming plate. Thus, operation of such devices was extremely fatiguing and required a two-step procedure; the device was moved and positioned and then the plunger was thrust against the building material which had been placed in the device's hopper by the operator or another workman. With the advent of power driven curb making machines, an operator's primary responsibility became the steering of the device over the desired course. The power driven devices are propelled along the ground by the pushing action of the engine or motor driven plunger or ramming plate against the building materials in the molding region.
One concern experienced with the making of curbs or barrier walls for smaller applications was the strength of the curb produced. Most extrusion type curb making machines, particularly those of the small, hand operated variety, did not enable the operator to strengthen the curb with internal reinforcement bars or wires. Ultimately, however, a hand operated machine with a power driven plunger was equipped with slots and/or apertures in the ramming plate which permitted the operator to introduce reinforcement bars or wires into the material being molded into a curb. The reinforcement problem is no longer a concern in curb making for smaller applications, however, because various fibrous materials, such as polypropylene fiber, can be added to the mixture of concrete, cement, or other building material which provide the material with the needed strength. Thus, the use of reinforcement bars or wires, for practical purposes, can be eliminated, thereby eliminating the need for a device that permits the introduction of reinforcement bars into the material.
The advancements and developments in the art of curb making have reduced the time consumed and the energy and manpower expended, but there is still room for improvement. It is still extremely time consuming to change from one curb configuration to another, for example, a change from a curb and gutter to a driveway. With many curb making machines, the curb configuration cannot be changed. In those cases the concrete or cement must be worked by hand to the desired configuration or another machine with the desired mold configuration must be used. Other curb making machines have features which can modify the configuration of the extruded concrete or cement without changing the extrusion mold. However, the modifications possible are limited and the components needed to provide the ability to modify add bulk and weight to the curb making machine. Some of the curb making machines have removable extrusion molds which can be interchanged so that the desired mold can be attached to the machine. But, the removal and changing of an extrusion mold is complex and has required considerable time and effort. Usually, such an exchange requires the disassembly of much of the machine, and in some cases, the disassembly of almost the entire feed mechanism. Moreover, the versatility of exchangeable extrusion molds has not been heretofore available in the small, hand operated curb making machines.
Accordingly, it would be an improvement in the art to provide an apparatus which would have the versatility of interchangeable extrusion molds that could be easily and quickly exchanged. It would also be an improvement in the art to provide interchangeable compacting plates or members to correspond to the various extrusion molds, particularly if such plates or members could also be easily and quickly exchanged. Further, it would be an improvement in the art to provide such versatility for the smaller, hand operated curb making machines that are used for yard purposes and to reach areas ordinarily inaccessible to the larger highway machines. Such apparatus are disclosed and claimed herein.